The gloves are off and the punches have already started flying. In the battle between the Bay State’s two shores, which region will get the knockout?

Illustration by John S. Dykes. Click to view larger, and see reader feedback on the North and South Shore boundaries on the interactive map below.

Route 1 or Route 3. Roast beef sandwiches or bar pizza. Polo club or yacht club. North Shore or South Shore. You’re either one or the other. And once you make your choice, there’s a good chance you’ll never cross over to the other side.

It turns out that this regional rivalry is older than the nation itself—starting with the Pilgrims who landed in Plymouth and the Puritans who landed in Salem, forming two separate colonies. “There is some difference in sensibility from the very beginning,” says Peter Drummey, the Stephen T. Riley librarian at the Massachusetts Historical Society. “The pride of place goes back a long time.”

Four centuries later, the differences are as apparent as ever. Which is why we decided it was about time we took this brawl to the streets, polling a panel of loyal North Shore and South Shore denizens—including staffers, local notables, and you, dear reader—to determine which territory would come out on top.

Speaking of territory, which cities and towns make up the North Shore and the South Shore? It’s a hotly contested question that depends entirely on where you live. One Marshfield native on staff, for instance, insists that the South Shore is “all the land that 3A (the scenic route) touches. Nothing more, nothing less.” For the purposes of this battle royale, we’ve combined the definitions from the North and South Shore chambers of commerce and the Massachusetts Office of Coastal Zone Management (see map above)—and yes, that includes towns that aren’t directly on the water.

It turns out that North Shore and South Shore natives do have one thing in common: a steadfast, if not calculating, unfamiliarity with their regional counterpart. “I grew up in Duxbury,” says Drummey, and even though he’s lived in Boston his whole adult life, “I still think of the North Shore as foreign territory.”